This invention relates to a novel process for the oxidation of methyl benzenes. More particularly, this invention relates to an improved process for the oxidation of methyl benzenes with air or oxygen in the presence of acetic acid, P.sub.2 O.sub.5, and sulfuric acid under mild conditions to form a phenolic acetate and formaldehyde or methylene diacetate. These compounds may then be converted to the corresponding phenolic compound and formaldehyde or paraformaldehyde by, for example, pyrolysis.
Earlier work of Grozhan et al, (Doklady Akad. Nauk, SSSR, 204, No. 4,872) established that acid catalyzed oxidation of toluene at high temperature and pressure in acetic anhydride followed by saponification of the reaction product gave phenol in modest yield. More recent work of Lyons, Suld and Shinn application Serial No. 945,747 has shown that phenyl acetate, methylene diacetate and acetic acid are the major products of the acid catalyzed air oxidation of toluene in acetic anhydride. This reaction is also characterized by relatively high temperatures and pressures. In copending application, Ser. No. 957,614, Suld et al. have demonstrated that when methyl benzenes are oxidized in acetic anhydride, but in the added presence of benzaldehyde, the reaction may be carried out at much milder temperatures and pressures then heretofore was possible. The use of relatively costly acetic anhydride in this reaction, however, made such a process economically less attractive than desired.